If you call valve amp OP stage impedance 'very high' then you can take any amplifier outputting 50W into 8 ohms and give it a high output impedance by feeding it into a reversed OP tx. If it was a class A amp with little or no negative feedback that would satisfy your conditions, n'est ce pas?

Originally posted by wakibaki If you call valve amp OP stage impedance 'very high' then you can take any amplifier outputting 50W into 8 ohms and give it a high output impedance by feeding it into a reversed OP tx. If it was a class A amp with little or no negative feedback that would satisfy your conditions, n'est ce pas?